The present invention relates to steering wheels for motor vehicles, and more particularly, to impact energy absorbing steering wheels.
U.S. Pat. No. 3,016,764 issued Jan. 16, 1962 to R. H. Fredericks et al. for a "Safety Steering Wheel" discloses a two-stage collapsible steering wheel comprising a flexible rim steering wheel having a steel armature that provides the necessary torsional stiffness for steering the vehicle while permitting axial displacement of the rim under relatively low impact load conditions. The armature is supported on a central energy absorbing structure constructed and arranged to progressively collapse under load to absorb any impact energy over and above that causing axial displacement of the rim.
Since the development of the Fredericks et al steering wheel assembly, attempts have been made to substitute plastic materials for the all steel construction. The primary advantage of the use of plastic materials is the weight saving that may be achieved, a factor that is becoming more critical as the demand grows in the marketplace for more fuel efficient vehicles. Prior art patents documenting the evolution of the all metal steering wheel assembly toward an all plastic steering wheel include U.S. Pat. Nos. 3,167,974 issued Feb. 2, 1965 to K. Wilfert for a "Steering Wheel", 3,802,291 issued Apr. 9, 1974 to F. E. Young, Jr. et al. for a "Soft Steering Wheel Rim", 3,938,404 issued Feb. 17, 1976 to G. Murase et al. for an "Energy Absorbing Steering Assembly" and 4,010,658 issued on Mar. 8, 1977 to G. H. Muller et al. for a "Steering Wheel Having a Flexible Rim".
All of these prior art patents disclose composite structures, i.e., steering wheel assemblies utilizing steel and plastic materials. The present invention provides a steering wheel assembly in which the only major metal component is the metal hub for mounting the steering wheel on the vehicle steering shaft.